RESUMO

O controle de estímulos exercido por algumas propriedades ou aspectos de um estímulo antecedente contingente ao reforço é definido como controle restrito de estímulos. O objetivo do estudo foi investigar o controle discriminativo por elementos de estímulos visuais compostos em tarefas de discriminação simples. Participaram catorze pré-escolares (seis com autismo e oito com desenvolvimento típico) entre quatro e seis anos de idade. O procedimento envolveu o ensino de discriminação simples entre um par de estímulos visuais compostos por dois elementos. Em seguida, foram realizadas sondas para avaliar o controle discriminativo por cada elemento do estímulo composto (S+ e S-). Todas as crianças responderam aos dois elementos do S+ e não responderam, ou responderam com baixa frequência, aos elementos do S- dos três pares de estímulos treinados e avaliados separadamente. Os resultados demonstraram que os pré-escolares com autismo e desenvolvimento típico responderam sob controle dos elementos dos estímulos S+. O investimento no estudo do controle restrito de estímulos pode contribuir na compreensão desse fenômeno como um processo comportamental básico.

The control of stimuli exercised by some of the properties or aspects of an antecedent stimulus contingent upon reinforcement is defined as restricted control of stimuli. The aim of this study was to investigate discriminative control by the elements of a composite visual stimuli in simple discrimination tasks. Fourteen preschool children (six with autism and eight typical development) between four and six years old participated. The procedure involved the simple discrimination learning between a pair of visual stimuli composed of two elements. Then, probes were carried out to evaluate the discriminatory control for each element of stimulus compound (S+ and S-). All children responded to both elements of S+ and did not respond or responded with low frequency to the elements of S- for the three pairs of stimuli trained and evaluated separately. The results showed that preschool children with autism and typical development responded under control of all the elements S+ stimuli. The investment in the study of the restricted control of stimuli can contribute to the understanding of this phenomenon as a basic behavioral process.

RESUMO

Abstract This study investigated the effects of pseudoword discrimination training that either required or didn't require selection responses upon control by stimulus elements and recombination of elements, and upon stimulus observation. Eight undergraduate students were exposed to two conditions with discriminative training and stimulus control test. Condition SEL required selecting the S+, and condition OBS only required observation. Test results suggest that selection responses did not affect control by the elements or the recombination of elements in the pseudowords. Four participants presented restricted stimulus control. This control was extended in the additional DOR condition, which required differential observation of the elements, and was accompanied by increases in S+ observation. Increased stimulus control, promoted by the DOR, should still be evaluated independently of previous teaching conditions.

Resumo Este estudo investigou o efeito de treino discriminativo de pseudopalavras com e sem a exigência de resposta de seleção sobre o controle por elementos e recombinações de elementos e sobre a observação dos estímulos. Oito universitários realizaram duas condições com treino discriminativo e teste de controle de estímulos. Na condição SEL, requeria-se uma resposta de seleção do S+; na condição OBS, apenas a observação. A resposta de seleção não foi determinante no controle pelos elementos e pela recombinação de elementos. Quatro participantes apresentaram controle restrito. Esse controle foi ampliado na condição adicional DOR, que requeria a observação diferencial dos elementos, e foi acompanhado por aumento da observação do S+. A ampliação do controle de estímulos, ocasionada pelo DOR, ainda requer avaliação independente de condições de ensino anteriores.

RESUMO

This study established a simple simultaneous discrimination between a pair of two-element compound visual stimuli in children (Experiment 1) and bees (Melipona quadrifasciata, Experiment 2). The contingencies required discriminative control by the compound and the question was whether the accurate stimulus control reached at this level would hold for each individual element of the compound. After baseline reached stability, probe trials assessed stimulus control by each single element of both S+ and S-. Average data showed that children (Exp. 1) tended to show stimulus control by a single element of the S+ compound. In Experiment 2 three of four bees showed stimulus control by both elements of S+ and did not respond or responded only infrequently to the elements of the S-. The children's decline in discrimination accuracy in probe trials, along with its maintenance during the baseline, replicated previous findings showing the development of restricted stimulus control (RSC). The precise stimulus control shown by the bees indicated that all elements correlated with reinforcement acquired stimulus control over their behavior; this confirms the extensive literature on visual discriminative learning in bees, but due to the small number of subjects it is premature to say that bees do not develop RSC...

Assuntos

RESUMO

This study established a simple simultaneous discrimination between a pair of two-element compound visual stimuli in children (Experiment 1) and bees (Melipona quadrifasciata, Experiment 2). The contingencies required discriminative control by the compound and the question was whether the accurate stimulus control reached at this level would hold for each individual element of the compound. After baseline reached stability, probe trials assessed stimulus control by each single element of both S+ and S-. Average data showed that children (Exp. 1) tended to show stimulus control by a single element of the S+ compound. In Experiment 2 three of four bees showed stimulus control by both elements of S+ and did not respond or responded only infrequently to the elements of the S-. The children's decline in discrimination accuracy in probe trials, along with its maintenance during the baseline, replicated previous findings showing the development of restricted stimulus control (RSC). The precise stimulus control shown by the bees indicated that all elements correlated with reinforcement acquired stimulus control over their behavior; this confirms the extensive literature on visual discriminative learning in bees, but due to the small number of subjects it is premature to say that bees do not develop RSC.(AU)

Assuntos

RESUMO

Teaching the first instances of arbitrary matching-to-sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimenter-even when stimulus control shaping procedures are used. We present, in this study, efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two components-one identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control.(AU)

Assuntos

RESUMO

Teaching the first instances of arbitrary matching-to-sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimenter-even when stimulus control shaping procedures are used. We present, in this study, efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two components-one identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control.

Assuntos

RESUMO

Teaching the first instances of arbitrary matching to sample to nonhumans can prove difficult and time consuming. Stimulus control relations may develop that differ from those intended by the experimenter - even when stimulus control shaping procedures are used. This paper reports efforts to identify sources of shaping program failure with a capuchin monkey. Procedures began with a baseline of identity matching. During subsequent shaping trials, compound comparison stimuli had two components - one identical to and another different from the sample. The identical component was eliminated gradually by removing portions across trials (i.e., subtracting stimulus elements). The monkey performed accurately throughout shaping. At a late stage in the program, probe tests were conducted: (1) arbitrary matching trials that had all elements of the identical comparison removed and (2) other trials that included residual elements. During the test, the monkey performed at low levels on the former trials and higher levels on the latter. These results suggested that higher accuracy was due merely to continued control by the residual elements: the target arbitrary matching relations had not been learned. Thus, it appears that procedures that gradually transform identity matching baselines into arbitrary matching can fail by inadvertently shaping restricted control by residual elements. Subsequent probes at the end of the shaping series showed a successful transfer of stimulus control from identity to arbitrary matching after further programming steps apparently overcame the restricted stimulus control.

RESUMO

This paper reports use of sample stimulus control shaping procedures to teach arbitrary matching-to-sample to 2 capuchin monkeys (Cebus apella). The procedures started with identity matching-to-sample. During shaping, stimulus features of the sample were altered gradually, rendering samples and comparisons increasingly physically dissimilar. The objective was to transform identity matching into arbitrary matching (i.e., matching not based on common physical features of the sample and comparison stimuli). Experiment 1 used a two-comparison procedure. The shaping procedure was ultimately effective, but occasional high error rates at certain program steps inspired a follow-up study. Experiment 2 used the same basic approach, but with a three-comparison matching task. During shaping, the monkey performed accurately until the final steps of the program. Subsequent experimentation tested the hypothesis that the decrease in accuracy was due to restricted stimulus control by sample stimulus features that had not yet been changed in the shaping program. Results were consistent with this hypothesis, thus suggesting a new approach that may transform the sample stimulus control shaping procedure from a sometimes useful laboratory tool to a more general approach to teaching the first instance of arbitrary matching performances to participants who show protracted difficulties in learning such performances.

Assuntos